Every. Presentation. EVER.

If you absolutely MUST have a slideshow, like say, you’re giving a presentation about works of art, use it just to show the works of art. Or else, if your presentation is just a lecture, have a one-slide PPT that gives the the outline of your talk. I love it when people do this because it makes it easier to take notes and know when the hell the speechifier is going to finish up so I can go off in a corner somewhere and take a nap.